Sad news out of Miami last night: former Bears safety Dave Duerson was found dead in his home at the age of 51. Duerson holds a special place in our hearts because he was the inspiration for our AV-based similarity scores, so as a tribute here is a re-run of Doug's introductory post on the system from July 2008:
Awhile back I was talking football with this kid I know. I brought up Dave Duerson as an example of something or other, and the kid had to confess to never having heard of Duerson. I scolded the kid and started muttering to myself. Never heard of Dave Duerson. Sheesh. Ever heard of the 85 Bears???!!! Awful.
A few months later, I had the occasion to do some research on Lemar Parrish. As a completely honest blogger, I have to confess that, before looking him up, I didn't know much more about Parrish than the kid did about Duerson. And Parrish was a better player. According to AV, he is the best eligible post-merger defensive back not currently in the Hall of Fame (at least until Aeneas Williams becomes eligible).
So I did the math, and realized that if you map Duerson's NFL career onto the kid's life, it looks very similar to the mapping of Parrish's career onto mine. Duerson's NFL debut happened a few months before the kid was born. Duerson retired when the kid was ten. Likewise, Parrish debuted the year before I was born, and he retired when I was 11. So the kid's only crime was being a toddler when the NFL --- and indeed the entire sports world --- attained perfection, which of course coincided with my being 12 to 14 years old.
Anyway, what's needed in these situations is the ability to translate a guy to other eras. Off the top of my head, I couldn't describe Duerson very well to the kid: he was a safety who wasn't a hall of famer but was pretty good. That really doesn't say much.
So I decided to whip up a very, very simple similar-player generator.
If you visit baseball- and/or basketball-reference, you know that they both have fairly sophisticated similarity scores on their player pages. What I'm doing here is much, much less ambitious. I'm not interested in finding safeties whose playing style is similar to Duerson's, or cornerbacks whose style is similar to Lemar Parrish's; I just don't think that's possible from looking at the stat lines.
I just want a way to tell the kid that Duerson is Merton Hanks without the neck. Or, for the even younger set, Mike Brown with a little more staying power. Likewise, I feel I have a better handle on where Lemar Parrish fits in the grand scheme of things by regarding him as just a tick below Mike Haynes, or as Eric Allen with a longer career.
The method is very simple. Well, after you've computed everyone's approximate value for every season, it's simple. For each pair of players, you give them 100 "similarity points" if they both occupy three-dimensional space and breathe air. Then you subtract one similarity point for each point of difference in their best-season AVs, .95 of a similarity point for each point of difference in their second-best-season AV, .90 of a similarity point for each point of difference in their third-best-season AV, and so on.
I do this instead of simply comparing career AVs because I want to measure the "shape" of the career in addition to its value. Terrell Davis and Corey Dillon have pretty similar career AV totals. But I wouldn't call their careers similar, because Davis's value was largely concentrated in a couple of seasons, whereas Dillon's was spread out over several good-but-not-great years. In this method, Davis's best comps are Lawrence McCutcheon, William Andrews, Billy Sims, and the like. Dillon's comps are Jerome Bettis, Herschel Walker, and Earnest Byner.
[Please remember, I'm not trying to identify backs who were stylistically similar to Dillon. Just backs who had similar kinds of careers in terms of value and length.]
So here, according to the system, are Duerson's best comps:Dave Duerson | 100 | 18 12 11 11 4 4 3 2 2 2 1 Merton Hanks | 85 | 13 12 12 11 7 6 5 4 2 David Fulcher | 85 | 15 11 11 7 6 5 4 0 Glen Edwards | 84 | 15 10 10 10 8 6 5 4 3 2 2 Mike Brown | 84 | 17 11 7 7 6 3 2 1 Ken Ellis | 84 | 20 12 10 8 8 8 1 1 1 0 0 Eric Turner | 83 | 17 9 7 6 6 4 3 3 3 Blaine Bishop | 83 | 14 12 9 9 7 6 6 5 2 1
The number between the pipes is the similarity score between Duerson and the given player. The numbers that follow are that player's AVs arranged from best to worst (not chronologically).
Lemar Parrish's comps:Lemar Parrish | 100 | 15 14 13 13 12 12 11 10 10 9 5 4 1 Mike Haynes | 84 | 17 16 16 14 14 13 13 11 9 7 3 3 1 1 Louis Wright | 83 | 18 17 13 11 11 10 10 7 7 6 6 4 Aeneas Williams | 81 | 18 17 15 14 11 10 10 9 7 6 5 5 4 3 Deion Sanders | 79 | 20 16 15 15 14 13 13 13 8 7 4 4 3 2 Eric Allen | 79 | 18 15 13 12 11 9 8 7 7 7 7 6 6 5 Mel Blount | 79 | 18 16 14 14 14 14 9 9 8 7 7 7 6 6 Jake Scott | 79 | 17 15 14 14 13 9 9 9 8
Now, for you youngsters out there, I'll just pick a few random guys from my youth who I think may not have been remembered to the extent that they should have been, and I'll try to give you an idea of how good they were in terms of more recent players.
Art Still =~ Willie McGinest
Fred Smerlas =~ Ted Washington or Sam Adams
Matt Blair =~ Chris Spielman or Donnie Edwards
Jerry Robinson =~ Tedy Bruschi or Chad Brown
Herm Edwards =~ Brock Marion
Gary Barbaro =~ Nate Clements or Donnie Abraham Tony Parrish or Blaine Bishop
Jacob Green =~ a slightly-poor man's Leslie O'Neal
E.J. Junior =~ Mike Peterson
Tom Jackson =~ Mo Lewis
Keena Turner =~ Jamie Sharper
Deron Cherry =~ Brian Dawkins
This entry was posted on Friday, February 18th, 2011 at 11:17 am and is filed under Obituaries. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.